Spherical coverage antenna systems, devices, and methods

ABSTRACT

The present subject matter relates to systems, devices, and methods for controlling the directional gain of an antenna. in some embodiments, an antenna for wireless communications includes a monopole antenna element and at least one passive beam-steering element that is spaced apart from the monopole antenna element. The at least one passive beam-steering element is configured to steer a signal beam from the monopole antenna element in a direction substantially orthogonal to the monopole antenna element.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of U.S. Patent Application Ser. No. 62/796,390, filed Jan. 24, 2019, the disclosure of which is incorporated herein by reference in its entirety. This application also relates to U.S. application Ser. No. ______ (to be assigned), entitled SYSTEMS AND METHODS FOR VIRTUAL GROUND EXTENSION FOR MONOPOLE ANTENNA WITH A FINITE GROUND PLANE USING A WEDGE SHAPE and ______ (to be assigned), entitled METHOD FOR INTEGRATING ANTENNAS FABRICATED USING PLANAR PROCESSES commonly owned and filed on Jan. 24, 2020, both of which also claim priority to U.S. Provisional Patent Application Ser. No. 62/796,390, filed Jan. 24, 2019, the contents of all applications identified above which are incorporated by reference herein.

TECHNICAL FIELD

The subject matter disclosed herein relates generally to radio frequency antenna systems. More particularly, the subject matter disclosed herein relates to methods and designs for implementing steerable beams with compact low-cost hardware.

BACKGROUND

In applications of cellular communication in mm-wave frequencies, conventional systems have a problem getting enough signal transmitted to achieve a good signal link budget. Since one end of the link in such cellular systems is a mobile terminal, which is often battery operated, the energy available for transmission can be limited and the link efficiency has to be improved, which is commonly achieved by increasing the higher directional antenna gain. It is further desirable that the coverage in a wide array of directions is available, either through the inclusion of multiple different directional antenna elements or through programmable steering of the directional antenna gain.

Conventional antenna systems have so far proven ineffective in providing such directional gain that can be programmed in different directions under power efficient conditions for battery operated terminals.

SUMMARY

In accordance with this disclosure, systems, devices, and methods for controlling the directional gain of an antenna that can be programmed in different directions are provided. In one aspect, an antenna for wireless communications is provided. The antenna includes a monopole antenna element and at least one passive beam-steering element that is spaced apart from the monopole antenna element. The at least one passive beam-steering element is configured to steer a signal beam from the monopole antenna element in a direction substantially orthogonal to the monopole antenna element.

In another aspect, a method for steering a signal beam at an antenna includes positioning at least one passive beam-steering element near a monopole antenna element and steering a signal beam from the monopole antenna element in a direction substantially orthogonal to the monopole antenna element.

In another aspect, an antenna array for a wireless communications system includes a plurality of antennas arranged in an array about a wireless communications device. Each of these antennas can include a monopole antenna element and at least one passive beam-steering element spaced apart from the monopole antenna element, wherein the at least one passive beam-steering element is configured to steer a signal beam from the monopole antenna element away from the wireless communications device in a direction substantially coplanar with the array.

Although some of the aspects of the subject matter disclosed herein have been stated hereinabove, and which are achieved in whole or in part by the presently disclosed subject matter, other aspects will become evident as the description proceeds when taken in connection with the accompanying drawings as best described hereinbelow.

BRIEF DESCRIPTION OF THE DRAWINGS

The features and advantages of the present subject matter will be more readily understood from the following detailed description which should be read in conjunction with the accompanying drawings that are given merely by way of explanatory and non-limiting example, and in which:

FIGS. 1A and 1B are a perspective side view and a top view, respectively, of an antenna according to an embodiment of the presently disclosed subject matter;

FIG. 2 is a graph showing directional gain at a range of tuning settings of an antenna according to an embodiment of the presently disclosed subject matter;

FIG. 3 is a schematic representation of a beam-steering arrangement for an antenna according to an embodiment of the presently disclosed subject matter;

FIG. 4 is a perspective top view illustrating a directional radiation field of corner-mounted antennas in a wireless communications device according to an embodiment of the presently disclosed subject matter;

FIGS. 5A through 5E are perspective top views illustrating steering of a directional radiation field of an antenna according to an embodiment of the presently disclosed subject matter;

FIGS. 6A and 6B are perspective side views of an edge-mounted antenna in a wireless communications device according to an embodiment of the presently disclosed subject matter;

FIG. 7A is a top view illustrating a directional radiation field of an edge-mounted antenna in a wireless communications device according to an embodiment of the presently disclosed subject matter;

FIG. 7B is a graph showing directional gain at a range of tuning settings of an antenna according to an embodiment of the presently disclosed subject matter;

FIG. 8 is a perspective side view of an antenna mounted as a module in a wireless communications device according to an embodiment of the presently disclosed subject matter;

FIG. 9 is a side perspective view of an antenna module according to an embodiment of the presently disclosed subject matter; and

FIG. 10 is a circuit diagram representing an antenna array for a wireless communications system according to an embodiment of the presently disclosed subject matter.

DETAILED DESCRIPTION

The present subject matter provides systems, devices, and methods for controlling the directional gain of an antenna, particularly for an antenna configured for communication in mm-wave frequencies. In one aspect, the present subject matter provides an antenna structure for wireless communications. As illustrated in FIGS. 1A and 1 B, the antenna, which is generally designated 100, includes a monopole antenna element 110. In some embodiments, the monopole antenna element 110 is sized based on the desired range of operating frequencies in which it will communicate. In this regard, in some embodiments, the monopole antenna element 110 can have a height equal to about one-quarter of a wavelength of electromagnetic waves configured to be propagated by the antenna 100, wherein a wavelength is equivalent to one wavelength of an operating or resonating frequency of the antenna system. In some embodiments, the monopole antenna element 110 is a tunable antenna, wherein the operating frequency range of the monopole antenna element 110 can be varied. The principles discussed herein are applicable to a monopole antenna element 110 having a different size, such as those having heights between, and including, about 0.1 and 0.4 wavelengths. Although only a single monopole antenna element 110 is shown in these figures, the principles discussed herein can be applied to antenna configurations that include multiple antennas. As a result, in other embodiments, antenna 100 can include a plurality of monopole antenna elements 110.

In some embodiments, the antenna 100 further includes at least one passive beam-steering element 120 that is spaced apart from the monopole antenna element. The at least one passive beam-steering element 120 is configured to steer a signal beam from the monopole antenna element 110 in a direction substantially orthogonal to the monopole antenna element 110. Those skilled in the art will appreciate that the reciprocity theorem is valid for the antennas and electromagnetic propagation, and the receive or transmit scenario are interchangeable scenarios and any mention herein according to a receive or transmit scenario is used for explanatory and example purposes only and should not be construed as limiting the present subject matter in any way. For effective operation as a reflector, the at least one passive beam-steering element 120 can be positioned on the opposite side of the monopole antenna element 110 with respect to a desired direction of a signal beam from the monopole antenna element 110 and have a length, which can be similar to the monopole, and base termination, which is usually grounded, such that the signal beam is steered in a direction away from the at least one passive beam-steering element 120. Alternatively or in addition, in some embodiments, an impedance to the at least one passive beam-steering element 120 can be tuned such that the at least one passive beam-steering element 120 is operable to steer a signal beam from the monopole antenna element 110 in directions either towards the at least one passive beam-steering element 120 (director) or substantially away from the at least one passive beam-steering element 120 (reflector).

In some embodiments, each passive beam-steering element 120 is a passive parasitic element or passive monopole. In some embodiments, For example and without limitation, the antenna 100 can comprise two parasitic elements or more. For example, in the configuration shown in FIGS. 1A and 1B, the antenna 100 includes a first parasitic element 121, a second parasitic element 122 spaced apart from the first parasitic element 121, and the monopole antenna element 110 is positioned generally between the first parasitic element 121 and the second parasitic element 122. In some embodiments, the first parasitic element 121 and the second parasitic element 122 are passive monopoles. In some embodiments, the first parasitic element 121 and the second parasitic element 122 each have a height that is substantially equivalent to or greater than a height of the monopole antenna element 110. In some embodiments, For example and without limitation, the first parasitic element 121 and the second parasitic element 122 have a height equal to approximately ¼ (0.25) wavelengths of the desired frequency operating range in the surrounding medium, although other element sizes can be effective in directing a signal beam from the monopole antenna element 110. In some embodiments, for example, parasitic elements having a height of approximately ⅝ (0.625) of a wavelength can be desirable due to its high horizontal gain. The parasitic elements can also be effective in some embodiments with heights in the range between about ⅛ (0.125) and ¾ (0.75) wavelengths.

In some embodiments, the inter-element distance of this array of elements can be less than half of the wavelength of electromagnetic waves configured to be propagated by the antenna 100. For example and without limitation, in some embodiments, the active and passive elements can be spaced apart with respect to one another based on the desired frequency range of operation for antenna 100. In some embodiments, the at least one passive beam-steering element 120 is positioned a small fraction of a wavelength from the monopole antenna element 110 so as to be in the near field of the monopole antenna element 110. In this regard, each of the at least one passive beam-steering element 120 can be spaced apart from the monopole antenna element 110 by a distance less than or equal to approximately ¼ (0.25) wavelengths of the desired operating frequency, which can provide efficient operation as a reflector in configurations in which the passive element is ‘grounded’. In some embodiments, the distance between elements can be much less than ¼ wavelengths, for example about 0.15 wavelengths, although the at least one passive beam-steering element 120 can also be effective in directing a signal beam from the monopole antenna element 110 at spacings between about 0.1 wavelengths and 0.7 wavelengths. In some embodiments, the closer the at least one passive beam steering element 120 is to the monopole antenna element 110, the greater the steering for a given amount of tuning. There is typically a tradeoff in efficiency, however, such that there will be an optimum spacing. In this arrangement, the passive beam-steering elements 120 can provide enough scattered energy to superpose with the radiation of the active monopole antenna element 110 to help steer a signal beam from the monopole antenna element 110 in a desired direction.

Although the embodiments illustrated in FIGS. 1A and 1B, and described herein, includes first parasitic element 121 and second parasitic element 122, other embodiments of the present subject matter can include one parasitic element or more than two parasitic elements. Furthermore, the inter-element spacing between each of the first parasitic element 121, the second parasitic element 122, and the monopole antenna element 110 can be designed to be substantially similar (For example and without limitation, all parasitic elements can be spaced substantially the same distance from the monopole antenna element 110) or different (For example and without limitation, one or more element positioned closer to the monopole antenna element 110 than others). In some embodiments, For example and without limitation, the inter-element spacing between each of the first parasitic element 121, the second parasitic element 122, and the monopole antenna element 110 can be selected based on the desired frequency range of operation for antenna 100. As discussed above, in some embodiments, the at least one passive beam-steering element 120 is positioned a small fraction of a wavelength from the monopole antenna element 110 so as to be in the near field of the monopole antenna element 110.

In addition to generally steering the signal beam in a desired direction, in some embodiments, the at least one passive beam-steering element 120 is tunable to selectively change the direction to which the signal beam is steered. In some embodiments, the signal beam can thus be steered towards any of a range of angles within a plane substantially orthogonal to the monopole antenna element 110. FIG. 2 is a graph showing the directional gain being adjustable based on different tuning settings of the antenna 100. For example, in some embodiments, the at least one passive beam-steering element 120 is tunable by varying an impedance between an end of each of the parasitic monopole elements and a ground element. An impedance to the at least one passive beam-steering element 120 can be adjustable to effectively become either more inductive or more capacitive. In this way, one or more of the at least one passive beam-steering element 120 can work as a reflector and/or a director where the impedance to the at least one passive beam-steering element 120 is primarily inductive or primarily capacitive, respectively, to steer a signal beam at the monopole antenna element 110 in a desired direction. Those having ordinary skill in the art will recognize, however, that the relationship between the impedance termination for the at least one passive beam-steering element 120 to achieve a given beam-steering configuration depends on the location of the at least one passive beam-steering element 120 with respect to the monopole antenna element 110. In some embodiments, the at least one passive beam-steering element 120 is tunable to provide coverage over 180 degrees within the plane substantially orthogonal to the monopole antenna element 110.

In some embodiments, for example, the interaction between the at least one passive beam-steering element 120 and the monopole antenna element 110 produces a radiation pattern having a multitude of opening angles (e.g., −3 dB bandwidth) for the signal beam main lobe. The at least one passive beam-steering element 120 can be tuned to effectively direct the main lobe to any of a range of directions by increasing the gain (e.g., to be greater than at least about 2 dB) in different overlapping and/or non-overlapping beam lobes. In this way, the operation of the antenna 100 can be controlled to establish a number of signal beams desired for a number of receiving or transmitting directions. In addition to controlling the direction of the signal beam from the monopole antenna element 110, the configuration and operation of the at least one passive beam-steering element 120 can further vary the ‘shape’ or directivity of the beam that is being steered. As the angle of the beam direction is programmed or otherwise changed, the shape of the beam may also be changed, including changes in the peak gain and the beam width in horizontal and vertical directions.

Depending on the number and/or arrangement of the at least one passive beam-steering element 120 about the monopole antenna element 110, the precision with which the direction of the signal beam can be steered can be varied. For example and without limitation, configurations incorporating more passive beam-steering elements may be able to provide greater control over the beam steering. Alternatively or in addition, spacing the first parasitic element 121 and second parasitic element 122 from the monopole antenna element 110 in different directions can provide additional degrees of freedom in the directions to which the beam can be steered. In some embodiments, for instance, the first parasitic element 121 is positioned in a substantially colinear arrangement with respect to the monopole antenna element 110, and the second parasitic element 122 is positioned in a substantially colinear arrangement with respect to the monopole antenna element 110. In some embodiments, this arrangement can include the first parasitic element 121, the second parasitic element 122, and the monopole antenna element 110 being arranged in a substantially co-planar array to enable the beam to be steered substantially within the plane. As illustrated in FIGS. 1A and 1B, for example, all of the first parasitic element 121, the second parasitic element 122, and the monopole antenna element 110 can be arranged on a common substrate, with the monopole antenna element 110 being offset relative to the at least one passive beam-steering element 120 generally in a desired direction of a signal beam.

Positioning the elements in such an arrangement, with the at least one passive beam-steering element 120 being positioned on an opposite side of the monopole antenna element 110 with respect to a desired direction of a signal beam from the monopole antenna element 110, a beneficial compromise between good broadside radiation (i.e., radiation in a direction substantially orthogonal to the monopole antenna element 110) and endfire radiation (i.e., radiation in a direction substantially aligned with the monopole antenna element 110, towards both 0 and 180 degree) can be achieved. In this arrangement, depending on the effective impedance to where each of the at least one passive beam-steering elements 120 can be tuned to act either as a tunable reflector for radiation in the broadside direction or as a tunable director for radiation in the endfire direction. Alternatively, in other embodiments in which the first parasitic element 121, the second parasitic element 122, and the monopole antenna element 110 are not all arranged in a single plane, the range of beam angles can be further varied such that the beam is steerable in both azimuth and elevation.

In some embodiments, a first impedance to the first parasitic element 121 and a second impedance to the second parasitic element 122 are each independently tunable. As illustrated in FIG. 3, for example, in some embodiments, the first parasitic element 121 is connected to a first impedance element 131 and the second parasitic element 122 is connected to a second impedance element 132. In some embodiments, the impedances can be tuned by connecting the at least one passive beam-steering element 120 to a tuning component through a transmission line. In some embodiments, for example, the impedance of the tuning component can be tuned by switching between a number of impedance elements.

The impedance elements can be realized as capacitive elements, inductive elements, transmission line elements, or any combination thereof that are connected through circuit connections or switching elements. Alternatively, in other embodiments, the impedance of the tuning component is varied by applying one or more tunable impedance element that changes impedance according to a variable electric or magnetic field, such as by using MEMS capacitors, varactors, or the like, or is digitally programmed to present a desired impedance. In some embodiments, one or both of the first impedance element 131 or the second impedance element 132 comprises one or more tunable element. Moreover, in some embodiments, one or more impedance elements comprises one or more fixed inductors or one or more fixed capacitors. For example, without limitation, one or both of the first impedance element 131 or the second impedance element 132 comprises one or more fixed inductors or one or more fixed capacitors.

In any configuration, for systems having multiple passive beam-steering elements 120, such as with the first parasitic element 121 and the second parasitic element 122, the impedances of each parasitic element can be tuned in a variety of different combinations to steer the signal beam in a corresponding number of different angles. In this way, by controlling the impedance to with first parasitic element 121 and the second parasitic element 122 (e.g., by controlling the impedance of the first impedance element 131 and/or second impedance element 132) to effectively become either more inductive or more capacitive, the combination of components of the at least one passive beam-steering element 120 can steer a signal beam at the monopole antenna element 110 in a desired direction.

Alternatively or in addition to one or more passive parasitic element or passive monopole, the at least one passive beam-steering element 120 can include one or more reflector 125 configured to reflect the signal beam in the direction substantially orthogonal to the monopole antenna element 110. This reflection can reduce backlobes and increase radiation away from the device into which the antenna 100 is incorporated. In some embodiments, the one or more reflector 125 is positioned about 0.25 wavelengths away from the monopole antenna element 110, although the reflector 125 can be effective in helping to direct the signal beam in a desired direction at any of a range of positions relative to the monopole antenna element 110. Accordingly, in some embodiments, the one or more reflector 125 can be positioned between about 0.1 and 0.7 wavelengths away from the monopole antenna element 110. In some embodiments in which all of the first parasitic element 121, the second parasitic element 122, and the one or more reflector 125 are provided, the one or more reflector 125 can be positioned generally behind the parasitic elements with respect to the monopole antenna element 110.

In some embodiments, the one or more reflector 125 is made of a suitable material that can at least partially reflect a signal beam from the monopole antenna element 110 in a direction substantially orthogonal to the monopole antenna element 110 and away from the one or more reflector 125. For example and without limitation, the one or more reflector 125 can comprise one or more of the following: copper, gold, silver, aluminum conductive paint or foil put onto a dielectric housing, or with plated vias through the dielectric housing. The outer surface of the one or more reflector 125 can be plated with a conductive material, such as any of those discussed above, so long as the material passivates the surface and conducts well at the frequencies of operation of the monopole antenna element 110.

The one or more reflector 125 can be implemented in a variety of different shapes or configurations with respect to the monopole antenna element 110. For example and without limitation, in some embodiments, the one or more reflector 125 can have a shape of a vertical wall or wide reflector. Alternatively, in some embodiments, the one or more reflector 125 can have a rod shape (i.e., cylindrical, rectangular, or any other suitable polygonal shape) that is approximately the same size or larger (i.e. taller and/or wider) than the monopole antenna element 110. The effectiveness of the one or more reflector 125 in helping to direct the signal beam in a desired direction can be increased by correspondingly increasing the width of the one or more reflector 125, although the additional benefit of added width can diminish once the reflector 125 extends a distance of about 0.5 wavelengths from either side of the monopole antenna element 110.

In some embodiments, the one or more reflector 125 is used in combination with the first parasitic element 121 and second parasitic element 122 to achieve steering angles that are not achievable by any element individually. For example and without limitation, whereas a single passive element can only steer the signal beam in two directions (toward and away from the passive element), configurations of the antenna 100 that include more elements and/or combinations of elements can provide greater control over the beam steering. In addition, the edge of an associated ground element (e.g., printed circuit board or other conductive ground plane) or other reflections can further affect the range of angles to which the signal beam can be steered. In some embodiments, therefore, the combination of elements of the at least one passive beam-steering element 120 is tunable to provide coverage over 180 degrees within the plane substantially orthogonal to the monopole antenna element 110

Regardless of the particular configuration of the antenna 100, improved performance of a mobile communications device can be achieved using the principles disclosed herein. In some embodiments, the antenna 100 can be arranged at or near a corner of a mobile communications device, generally designated 200, to provide a widely-steerable signal beam. As used herein, the term “corner” is used in its customary meaning to describe a position at or near the area at which two edges of the device 200 converge, including configurations in which the edges meet at a single point or the edges are connected by a rounded or chamfered corner. In one such configuration illustrated in FIG. 4, two antennas 100—a first antenna 100 a and a second antenna 100 b—are positioned at opposing corners of the mobile communications device 200. Each antenna 100 can be configured to exhibit high directional gain outwards in a direction of a respective corner of the mobile communications device 200. In some embodiments, the signal beam from the antenna 100 can be steerable to be directed out of either of the adjoining edges of the respective corner of the mobile communications device 200 and/or in any of a variety of directions approximately in a plane containing the two edges of the wireless communications device 200.

This positioning at the corners can help each antenna 100 to avoid interference from a user, such as from the user's hand or head interacting with the device 200. In addition, where the antenna 100 is steerable, positioning two antennas in this way can effectively provide beam-swept spherical coverage over 360 degrees with individual or simultaneous operation. As shown in FIGS. 5A-5E, for example, adjusting a tuning state of each antenna 100 can change the directional radiation field to orient the beam signal towards any of a range of directions.

By comparison, antenna systems that are used for communication in mm-wave frequencies typically include patch-like antennas that are mounted flat on the board (i.e., in the plane of the device 200) and radiate in a direction generally orthogonal to the plane of the device 200. Other conventional configurations use flat arrays that are side mounted along one or more edges of the device 200. Neither of these conventional antenna configurations can be mounted on a corner for radiation outwards in the direction of the corner.

Regarding the configuration of the antenna 100 for such an arrangement, the device 200 can comprise a ground plane 210, and the monopole antenna element 110 can be mounted on the ground plane 210 near the corner of the device 200. The at least one passive beam-steering element 120, such as the first parasitic element 121, the second parasitic element 122, and or the reflector 125 discussed above, can be positioned toward the terminal side of the antenna 100 to steer a signal beam from the monopole antenna element 110 away from the wireless communications device 200. In this kind of configuration, the monopole antenna element 110 is positioned between each of the at least one passive beam-steering element 120 and the corner of the device 200 such that the at least one passive beam-steering element 120 acting as a reflector helps to improve the directional gain in the direction of the corner.

Alternatively or in addition, an antenna 100 according to the present subject matter can be arranged on a side of the device 200, such as is illustrated in FIGS. 6A and 6B. FIG. 6A shows an example placement for the antenna 100 with respect to the scale of the device 200, and FIG. 6B shows a specific implementation of the antenna 100 at such a location. In the illustrated configuration, a monopole antenna element 110 is mounted near the edge of the device 200, and at least one passive beam-steering element 120, such as a first parasitic element 121, a second parasitic element 122, and or a third parasitic element 123, can be positioned around the monopole antenna element 110 to steer a signal beam from the monopole antenna element 110 outwardly from the edge of the device 200. As shown in FIGS. 7A and 7B, for example, in some embodiments, a directional radiation field of the antenna 100 can be steered about the edge of the device 200 to achieve an improved directional signal gain at any of a range of angles with respect to the edge.

In either position, the ground plane 210 can be shaped to help achieve the desired antenna radiation directivity outwards from the edge of the device 200. In some embodiments, for example, at least a portion of the edge of the ground plane 210 comprises a wedge or tapered shape 212 as shown in FIGS. 6A, 6B, and 8. The wedge or tapered shape 212 of the edge is configured to reflect the radiation emanating from the monopole antenna element 110 towards the direction of the edge. The wedge or tapered shape 212 acts as a virtual ground plane. The wedge or tapered shape 212 helps to generate such a radiation pattern because the incident field to the wedge or tapered shape 212 will be reflected and concentrated onto the direct incident field arriving at the monopole antenna element 110.

In any arrangement, in some embodiments, the elements of the antenna 100 can be integrated into a module 150 configured to be mounted as a surface-mount device on a wireless communications device. As illustrated in FIG. 8, each of the monopole antenna element 110 and the at least one passive beam-steering element 120 (e.g., first parasitic element 121 and second parasitic element 122) are mounted on the module 150. In addition, in some embodiments, the at least one passive beam-steering element 120 comprises a metallized edge of the module 150 that forms a reflector 125 configured to reflect the signal beam in the direction substantially orthogonal to the monopole antenna element 110, such as is shown in FIGS. 1A and 1B. As shown in FIG. 9, in some embodiments, the module 150 can further include an integrated circuit die 155 in communication with one or more of the monopole antenna element 110 and/or the at least one passive beam-steering element 120 and configured to interface with the wireless communications device 200. In some embodiments, the integrated circuit die 155 includes tuning circuitry configured to vary the operating frequency range of the monopole antenna element 110 and/or to vary the impedance to the at least one passive beam-steering element 120.

In such a configuration, in some embodiments, the module 150 is mounted on or integrated with a display of the device 200, and the display shield can be is used as the ground plane. The display in modern smart phones tends to extend to the edge and corner of the phone, which adds height restrictions on what can be mounted on the corner. Other restrictions include the presence of other antennas that often utilize most or all of the top and or bottom side of the phone. Despite these restrictions, the corner location can be a desirable location for mounting the module 150 because the top and the bottom of phones are often occupied by components like speakers, cameras, and low band antennas (400 MHz to 6 GHz). In this regard, the module 150 can be arranged or integrated into the device 200 along with modules having these additional functions. In addition, the size of module 150 can be smaller than conventional antenna systems, with the vertical arrangement of the monopole antenna element 110 being an area-efficient configuration. The corners are also the areas least likely to interact with a user, particularly if the antennas 100 are implemented on multiple corners and selectively activated.

With this configuration, the antenna 100 can then be mounted as a unit onto the device 200, whereby the elements do not need to be individually positioned and aligned with respect to the geometry of the device 200. Such modularization can ease the integration of mm-wave elements for cellular handsets, such as by providing plug-and-play installation.

As indicated above, a plurality of antennas 100 can be arranged together in an array on a device 200 to provide wide spherical coverage with individual or simultaneous operation. In some embodiments, such a plurality of antennas 100 can be arranged in an array about a wireless communications device 200. With selective placement, configuration, and tuning of the antennas 100, such an array can provide coverage over 360 degrees substantially within the plane of the array. Operation of such an array can be coordinated by a single controller 250. As illustrated in FIG. 10, for example, an antenna array for a mobile communications device 200 can include a first antenna 100 a, a second antenna 100 b, a third antenna 100 c, and a fourth antenna 100 d, which are each in communication with a controller 250 that is configured to selectively activate the antennas and/or to selectively tune their associated beam-steering elements to direct a signal beam in a desired direction with respect to the device 200. The use of passive beam-steering elements is more cost- and energy-efficient compared to conventional antenna configurations, and the disclosed antenna array only requires one receiver and transmitter branch.

In some embodiments, controller 250 is a microcontroller that can temporarily save a sequence of digital representations of data to be transmitted to a memory register. The data representation can be phase shifted by a digital representation of a phase rotator Φa, Φb, Φc and Φd by a digital (and complex i+jy) multiplication and temporarily store data to a memory for each antenna signal (e.g., to a memory a,b,c,d). The data can be clocked out to a digital to analog converter DAC and analog signal send to an analog multiplier (mixer) for each antenna and then transmitted through transmission lines to each antenna. The reverse case can be true for the reception of signal where each signal received from each antenna will be downconverted (mixer) to a lower frequency that is sampled through a analog to digital converter (ADC) and stored in memory a,b,c,d and digitally multiplied with a phasor belonging to each antenna. The values of the phasors Φa, Φb, Φc and Φd will be found by a lookup into a stored table and organized according to the direction to be transmitted or received from. The phasors can be separate from the phases of the impedances applied to the passive elements in each antenna 100. Each antenna will have a gain pattern defined by the tunable impedances and then the array factor will be determined by the phases across the antennas.

In some embodiments, for example, controller 250 can be operable to control the value and phase of the impedances applied to the passive elements such that one or more of antennas 100 can be configured to produce a radiation pattern comprising programmable beams collectively covering a coverage angle (i.e., for transmission, receiving, communication) of more than 135 degrees with 2 dB of antenna gain or more across the coverage angle. In some other embodiments, the one or more of antennas 100 can be configured to produce a coarser wide angle sweep, with programmable beams collectively covering a coverage angle of more than or equal to 180 degrees with 0 dB of antenna gain or more across the coverage angle (laterally). In still other embodiments, the one or more of antennas 100 can be configured to produce a fine angle sweep with higher gain, with programmable beams collectively covering a coverage angle of more than 90 degrees with 6 dB of antenna gain or more across the coverage angle (laterally). As discussed above, the beam shape or directivity can also be changed as the angle of the beam direction is programmed.

The values of the programming (e.g. switch setting of the tunable load) to be send to the impedance tuner is found by controller 250 by a lookup table of previous stored values according to the beam direction to be applied. The data is sent by a digital bus (e.g a serial bus such as 120 or MIPI RFFE) to the module 150 and/or impedance tuner die.

In any of the configurations and embodiments discussed above, the antenna 100 according to the present subject matter provides improvements over conventional antenna configurations for operation in mm-wave frequencies. The antenna 100 discussed above can provide a beam signal with high gain and directivity. In some embodiments, for example, the beam signal can provide substantially spherical coverage with a minimum number of antennas 100. This wide coverage can also be configured to radiate substantially entirely outwardly from the device 200, therefore providing less risk of the signal being obstructed by a user. The configurations and embodiments discussed herein can further minimize current consumption and signal distribution loss compared to conventional solutions since the use of passive beam-steering elements eliminates the losses due to switches and/or phase shifters.

The present subject matter can be embodied in other forms without departure from the spirit and essential characteristics thereof. The embodiments described therefore are to be considered in all respects as illustrative and not restrictive. Although the present subject matter has been described in terms of certain preferred embodiments, other embodiments that are apparent to those of ordinary skill in the art are also within the scope of the present subject matter. 

What is claimed is:
 1. An antenna for wireless communications comprising: a monopole antenna element; and at least one passive beam-steering element spaced apart from the monopole antenna element, wherein the at least one passive beam-steering element is configured to steer a signal beam from the monopole antenna element in a direction substantially orthogonal to the monopole antenna element.
 2. The antenna of claim 1, wherein the at least one passive beam-steering element is tunable to steer the signal beam towards any of a range of angles within a plane substantially orthogonal to the monopole antenna element.
 3. The antenna of claim 2, wherein the at least one passive beam-steering element is tunable to provide coverage with more than 0 dB antenna gain over 180 degrees within the plane substantially orthogonal to the monopole antenna element.
 4. The antenna of claim 1, wherein the monopole antenna element is positioned at or near a corner formed at the convergence of two edges of a wireless communications device, wherein the direction substantially orthogonal to the monopole antenna element is approximately in a plane containing the two edges of the wireless communications device.
 5. The antenna of claim 1, wherein the at least one passive beam-steering element comprises one or more reflector configured to reflect the signal beam in the direction substantially orthogonal to the monopole antenna element.
 6. The antenna of claim 1, wherein the at least one passive beam-steering element comprises one or more parasitic monopole element spaced apart from the monopole antenna element, wherein the at least one passive beam-steering element is tunable to selectively change the direction of the signal beam.
 7. The antenna of claim 6, wherein the at least one passive beam-steering element is tunable by varying an impedance between each of the one or more parasitic monopole element and a ground element.
 8. The antenna of claim 1, wherein the monopole antenna element and the at least one passive beam-steering element are integrated into a module configured to be mounted as a surface-mount device on a wireless communications device.
 9. The antenna of claim 8, wherein the module comprises an integrated circuit die in communication with one or more of the monopole antenna element or the at least one passive beam-steering element and configured to interface with the wireless communications device.
 10. The antenna of claim 9 where the integrated circuit die includes tuning circuitry configured to vary the operating frequency range of the monopole antenna element.
 11. The antenna of claim 8, wherein the at least one passive beam-steering element comprises a metallized edge of the module that forms a reflector configured to reflect the signal beam in the direction substantially orthogonal to the monopole antenna element.
 12. A method for steering a signal beam at an antenna, the method comprising: mounting a monopole antenna element onto a wireless communications device; positioning at least one passive beam-steering element near the monopole antenna element; and steering a signal beam from the monopole antenna element in a direction substantially orthogonal to the monopole antenna element.
 13. The method of claim 12, wherein steering the signal beam comprises tuning the at least one passive beam-steering element to steer the signal beam towards any of a range of angles within a plane substantially orthogonal to the monopole antenna element.
 14. The method of claim 13, wherein tuning the at least one passive beam-steering element comprises steering the signal beam with more than 0 dB antenna gain over 180 degrees within the plane substantially orthogonal to the monopole antenna element.
 15. The method of claim 12, wherein mounting the monopole antenna element onto the wireless communications device comprises positioning the monopole antenna element at or near a corner formed at the convergence of two edges of the wireless communications device, wherein the direction substantially orthogonal to the monopole antenna element is approximately in a plane containing the two edges of the wireless communications device.
 16. The method of claim 12, wherein the at least one passive beam-steering element comprises one or more reflector configured for reflecting the signal beam in the direction substantially orthogonal to the monopole antenna element.
 17. The method of claim 12, wherein the at least one passive beam-steering element comprises one or more parasitic monopole element spaced apart from the monopole antenna element, wherein steering the signal beam comprises tuning the one or more parasitic monopole element to selectively change the direction of the signal beam.
 18. The method of claim 17, wherein tuning the one or more parasitic monopole element comprises varying an impedance between each of the one or more parasitic monopole element and a ground element.
 19. The method of claim 12, comprising integrating the monopole antenna element and the at least one passive beam-steering element into a module; wherein mounting the monopole antenna element onto the wireless communications device comprises mounting the module as a surface-mount device onto the wireless communications device.
 20. The method of claim 19, wherein positioning at least one passive beam-steering element near the monopole antenna element comprises metallizing an edge of the module to form a reflector configured to reflect the signal beam in the direction substantially orthogonal to the monopole antenna element.
 21. An antenna array for a wireless communications system comprising: a plurality of antennas arranged in an array about a wireless communications device, each of the plurality of antennas comprising: a monopole antenna element; and at least one passive beam-steering element spaced apart from the monopole antenna element, wherein the at least one passive beam-steering element is configured to steer a signal beam from the monopole antenna element away from the wireless communications device in a direction substantially coplanar with the array.
 22. The antenna array of claim 21, wherein the at least one passive beam-steering element of each of the plurality of antennas is tunable to steer the signal beam towards any of a range of angles within a plane of the array, wherein the plurality of antennas are together tunable to provide coverage over 360 degrees within the plane of the array.
 23. The antenna array of claim 21, wherein the at least one passive beam-steering element of each of the plurality of antennas comprises one or more reflector configured to reflect the signal beam away from the wireless communications device.
 24. The antenna array of claim 21, wherein the at least one passive beam-steering element of each of the plurality of antennas comprises one or more parasitic monopole element spaced apart from the monopole antenna element, wherein the one or more parasitic monopole element is tunable to selectively change the direction of the signal beam.
 25. The antenna array of claim 21, wherein each of the plurality of antennas is integrated into a module mounted as a surface-mount device on the wireless communications device.
 26. The antenna array of claim 21, wherein each of the plurality of antennas is positioned at a corner of the wireless communications device. 